Lesson 3. Read, Interpret, and Evaluate Data
Lesson 2 introduced basic charts for comparing categorical values, visualizing trends over time, and exploring relationships within data. It also explored the distinction between discrete and continuous dates in Tableau and introduced text tables and callout numbers to emphasize key insights. This lesson introduces additional basic charts and techniques.
Data skills | concepts
- Tableau
- Working with data
- Analyzing data
Learning objectives
- Create groups to normalize data, correct errors, and simplify categories.
- Apply hierarchies for better data organization.
- Use formatting strategically to enhance visual impact.
- Analyze data with table calculations.
- Visualize part-to-whole relationships effectively.
This tutorial is designed to support a multi-session Tableau for Research workshop hosted by The Ohio State University Libraries Research Commons. It is intended to help the ABSOLUTE beginner, or anyone who is relatively new to Tableau to build the skills and confidence to apply Tableau to research projects.
LESSON 3
Why Practice Matters
Data visualization is a craft. Like any creative discipline, mastering this craft requires exposure to a variety of styles, techniques, and best practices. Just as musicians or artists grow by studying different genres, data visualiers improve by analyzing a wide range of visual storytelling examples.
To sharpen your skills, make it a habit to explore and critically evalute real-world visualizations—both successful and flawed.
Inspiration and examples
Explore data journalism
Major news outlets often feature compelling data visualizations created by professional data journalists. Check out examples from: - CNN - The New York Times - The Washington Post
The DRAMA framework
The DRAMA Framework, first introducted in Lesson 1, is also useful for critically evaluating data visualizations. (Primeau, n.d.) It encourages you to consider five key dimensions about the source and integrity of the visual:
DRAMA Framework
Date
Relevance
Accuracy
Motivation
Authority
By applying the DRAMA framework, you can better interpret—or design—visualizations that are not only visually compelling but also credible, transparent, and contextually sound.
Groups and Hierarchies
Why group data in Tableau?
Grouping data is a powerful way to clean and organize your dataset. It allows you to:
- Normalize values – Combine similar entries to ensure consistency (e.g., merging “OH” and “Ohio”).
- Correct errors – Fix inconsistencies or typos in category names.
- Simplify categories – Consolidate detailed values into broader, more meaningful groups.
Groups are another great example where there more than one way to accomplish the same task!!!
The simpliest way to create a group in Tableau is to:
- Select one or more data points directly in the view.
- Click the paperclip icon 📎 that appears in the tooltip.
Create a text table showing the peak US chart positions for albums by five of your favorite artists.
- Start a new worksheet and rename it FavoriteArtistAlbum
-
Select the relevant fields
- Drag Artist to the Rows shelf.
- Place Peak US on the Columns shelf.
- Open Show Me and select Text Tables.
-
Select your top 5 favorite artists
- Click on your first favorite artist.
- Hold Ctrl (or Cmd on Mac) + Click to select the others.
- Click the paperclip icon 📎 on the tooltip for the last artist selected
-
Edit group alias
- Right-click the first artist.
- Select Edit Alias.
- Rename to Favorite artists.
- Right-click Favorite artists and choose ✔ Keep only
-
Adjust fields
- Drag Artist to the Rows shelf.
- Drag album_title to the Rows shelf.
- Remove Favorite artists from the Rows shelf
-
Rename group
- Right-click Artist (group) 1 in the Data Pane.
- Select Rename and type Favorite artists.
Video showing steps 1-9 in exercise 1
A second way to create a group in Tableau is to:
- Right-click a dimension or measure in the Data Pane
- Select Create > Group.
On the FavoriteArtistAlbum sheet, use the Data Pane to group 10 of your Favorite albums into a single group.
- Right-click album_title and select Create > Group
- Rename the group Favorite albums
-
Find and add albums to the group
- Click Find >> to search for the first album title.
- Under Find members, type the name of your first favorite album title and click Find All.
- When the album appears in the list, select it and click Group
- Alias the group Favorite albums
-
Repeat the process for each additional album
- Type the album name under Find members
- Click Find All
- Select the album
- Use the Add to: dropdown to add each additional album to Favorite albums.
- ✔ Include ‘Other’ to consolidate non-favorite titles
Video showing steps 1-4 in exercise 2
Creating custom hierarchies
Custom hierarchies help save space on a view and add interactivity by allowing users to drill down into more detailed levels of data. In Lesson 2, you saw how Tableau automatically creates a date hierarchy—YEAR, QUARTER, MONTH, and DAY—which can be expanded using the + symbol.
You can create your own hierarchies by stacking one dimension onto another in the Data Pane (or one measure onto another).
Let’s walk through an example:
- Duplicate the existing sheet
- Right-click the FavoriteAristsAlbums sheet tab.
- Select Duplicate.
- Rename the new sheet Hierarchies.
- Create a hierarchy
- In the Data Pane drag album_title and drop it onto Artists.
- Filter to show only your favorite albums
- Drag Favorite albums group to the Filters shelf.
- Select Favorite albums only.
- Expand or collapse the hierarchy
- Click the
+or-next to Artist to expand or collapse the hierarchy.
- Click the
Video showing steps 1-4 in example above